Authors:P. Aslanidis, V. Gaki, K. Chrissafis, and M. Lalia-Kantouri
the simultaneous TG/DTG–DTA technique in inert and oxidative atmospheres. Simultaneous TG-DTA coupled with MS was used for the analysis of the gaseous decomposition products in argon atmosphere, while Powder XRD was used for the verification of the
Authors:N. R. Sperandeo, C. V. Mattia, and Maria M. de Bertorello
The tautomeric binary system consisting of N-(3,4-dimethyl-5-isoxazolyl)-4-amino-1,2-naphthoquinone (1),m.p. 156‡C, and 2-hydroxy-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinon-4-imine (2),m.p. 218‡C, was studied by DTA-TG-DTG and IR spectrometry. Crystals of 1, left in contact with their mother liquor during 4 months, exhibited thermal behaviour similar to that of physical mixtures of 1 and 2, which reveal the presence of a eutectic at about 146‡C.
Authors:Caroline Miyazaki, Igor Medeiros, Jivaldo Matos, and Leonardo Rodrigues Filho
Dental composites can be improved by heat treatment, as a possible way to increase mechanical properties due to additional
cure (post-cure). Direct dental composites are essentially similar to the indirect ones, supposing they have the same indication.
Therefore, to establish a heat treatment protocol for direct composites, using as indirect (photoactivated by continuous and
pulse-delay techniques), a characterization (TG/DTG and DSC) is necessary to determine parameters, such as mass loss by thermal
decomposition, heat of reaction and glass transition temperature (Tg). By the results of this study, a heat treatment could be carried out above 160 °C (above Tg, and even higher than the endset exothermic event) and under 180 °C (temperature of significant initial mass loss).
.0 ± 0.2 mg for thermal analysis and l.0 ± 0.1 mg for XRD.
Simultaneous TG–DTG–DTA analyses were carried out using a thermal analyser STA 780, Stanton Redcroft (England). The samples were heated from 20 to 1,000 °C at a constant rate of 10 °C
of ammoxidation on thermal stability of carbonaceous materials characterised
by degree of coalification other than that of brown coal (Konin mine, Poland)
or sub-bituminous coal (Sośnica mine, Poland) was studied by thermogravimetric
(TG-DTG) method. Analysis of TG-DTG curves has shown that coal samples ammoxidised
at the higher temperature show slightly lower thermal stability. It has been
established the importance of the sequence in the processes of carbonisation
and ammoxidation. Both the amount of nitrogen introduced on the surface of
studied carbonaceous materials and the thermal stability of nitrogen groups
In this research, the relationship between particle size and combustion kinetics and combustion properties of lignite samples
was examined by utilizing the thermogravimetric (TG/DTG) and differential thermal analysis (DTA) techniques. The lignite samples
separated into different size fractions were subjected to non-isothermal thermogravimetric analysis between ambient and 900�C
in the presence of 50 mL min−1 air flow rate. Activation energy (E) and Arrhenius constant (Ar) of combustion reaction of each size was evaluated by applying Arrhenius kinetic model to the resulting data. Combustion
properties of the samples were interpreted by careful examination of the curves. The apparent activation energies in major
combustion region were calculated as 41.03 and 53.11 kJ mol−1 for the largest size (−2360+2000 μm) and the finest size (−38 μm), respectively.
Authors:F. W. Wilburn, J. H. Sharp, D. M. Tinsley, and R. M. McIntosh
The effect of procedural variables, including sample mass, heating rate, particle size and partial pressure of carbon dioxide, on TG, DTG and DTA curves for the decomposition of A. R. calcium carbonate and limestone has been studied. Such variables have a marked effect, similar in magnitude for both DTG and DTA. The effect of sample mass, or depth of undiluted sample, is shown to be due to an increase in the partial pressure of carbon dioxide within the reacting powder and has been called the bed-depth effect. This effect is most pronounced in nitrogen but is much reduced in carbon dioxide. Inert diluents have little effect on the TG curves but changing the composition of the inert carrier gas causes variations which are correlated with the thermal conductivity of the gas. Water vapour causes a lowering of the DTG and DTA peak temperatures.
Authors:J. H. Sharp, F. W. Wilburn, and R. M. McIntosh
TG, DTG and DTA curves of magnesite are dependent on procedural variables, especially sample mass, heating rate and partial pressure of carbon dioxide, in a similar manner to those of calcite , although the magnitude of the effect is less for magnesite. The first stage of the decomposition of dolomite varies with increasing partial pressure of carbon dioxide in an anomalous manner and hence the effects of these procedural variables (except heating rate) are not similar to those observed for magnesite and calcite. The second stage of the decomposition of dolomite is, however, strongly dependent on these procedural variables and behaves in a manner that would be predicted for a sample of calcite diluted with magnesia. A 1∶1 molar mixture of magnesite and calcite also behaves as would be predicted from the behaviour of the single carbonates but differently from that of dolomite.
In this research, non-isothermal combustion and kinetics of Silopi (Turkey) asphaltite samples were investigated by differential
scanning calorimetry (DSC) and thermogravimetry (TG/DTG). A sample size of 10 mg, heating rates of 5, 10, 15 and 20�C min−1 were used in the temperature range of 20–600�C, under air atmosphere. Two reaction regions were observed in DSC curves. The
first region is due to the evaporation of moisture in asphaltite sample whereas, release of volatile matter and burning of
carbon is called the second region.
A general computer program was developed and the results of four different kinetic models (Arrhenius, Coats-Redfern, Ingraham-Marrier
and Horowitz-Metzger) are compared and discussed with regards to their accuracy and the ease of interpretation of the kinetics
of thermal decomposition. In general similar activation energy values were obtained when the kinetic models are compared with
each other. It was also observed that there was no general trend in the activation energy values from the point of heating